 /*******************************************************************************
  * Copyright (c) 2000, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.runtime;

 /**
  * For new implementations consider using {@link SubMonitor}.
  *
  * A progress monitor that uses a given amount of work ticks
  * from a parent monitor. It can be used as follows:
  * <pre>
  * try {
  * pm.beginTask("Main Task", 100);
  * doSomeWork(pm, 30);
  * SubProgressMonitor subMonitor= new SubProgressMonitor(pm, 40);
  * try {
  * subMonitor.beginTask("", 300);
  * doSomeWork(subMonitor, 300);
  * } finally {
  * subMonitor.done();
  * }
  * doSomeWork(pm, 30);
  * } finally {
  * pm.done();
  * }
  * </pre>
  * <p>
  * This class can be used without OSGi running.
  * </p><p>
  * This class may be instantiated or subclassed by clients.
  * </p>
  *
  * @see SubMonitor
  */
 public class SubProgressMonitor extends ProgressMonitorWrapper {

     /**
      * Style constant indicating that calls to <code>subTask</code>
      * should not have any effect.
      *
      * @see #SubProgressMonitor(IProgressMonitor,int,int)
      */
     public static final int SUPPRESS_SUBTASK_LABEL = 1 << 1;
     /**
      * Style constant indicating that the main task label
      * should be prepended to the subtask label.
      *
      * @see #SubProgressMonitor(IProgressMonitor,int,int)
      */
     public static final int PREPEND_MAIN_LABEL_TO_SUBTASK = 1 << 2;

     private int parentTicks = 0;
     private double sentToParent = 0.0;
     private double scale = 0.0;
     private int nestedBeginTasks = 0;
     private boolean usedUp = false;
     private boolean hasSubTask = false;
     private int style;
     private String mainTaskLabel;

     /**
      * Creates a new sub-progress monitor for the given monitor. The sub
      * progress monitor uses the given number of work ticks from its
      * parent monitor.
      *
      * @param monitor the parent progress monitor
      * @param ticks the number of work ticks allocated from the
      * parent monitor
      */
     public SubProgressMonitor(IProgressMonitor monitor, int ticks) {
         this(monitor, ticks, 0);
     }

     /**
      * Creates a new sub-progress monitor for the given monitor. The sub
      * progress monitor uses the given number of work ticks from its
      * parent monitor.
      *
      * @param monitor the parent progress monitor
      * @param ticks the number of work ticks allocated from the
      * parent monitor
      * @param style one of
      * <ul>
      * <li> <code>SUPPRESS_SUBTASK_LABEL</code> </li>
      * <li> <code>PREPEND_MAIN_LABEL_TO_SUBTASK</code> </li>
      * </ul>
      * @see #SUPPRESS_SUBTASK_LABEL
      * @see #PREPEND_MAIN_LABEL_TO_SUBTASK
      */
     public SubProgressMonitor(IProgressMonitor monitor, int ticks, int style) {
         super(monitor);
         this.parentTicks = (ticks > 0) ? ticks : 0;
         this.style = style;
     }

     /* (Intentionally not javadoc'd)
      * Implements the method <code>IProgressMonitor.beginTask</code>.
      *
      * Starts a new main task. Since this progress monitor is a sub
      * progress monitor, the given name will NOT be used to update
      * the progress bar's main task label. That means the given
      * string will be ignored. If style <code>PREPEND_MAIN_LABEL_TO_SUBTASK
      * <code> is specified, then the given string will be prepended to
      * every string passed to <code>subTask(String)</code>.
      */
     public void beginTask(String name, int totalWork) {
         nestedBeginTasks++;
         // Ignore nested begin task calls.
 if (nestedBeginTasks > 1) {
             return;
         }
         // be safe: if the argument would cause math errors (zero or
 // negative), just use 0 as the scale. This disables progress for
 // this submonitor.
 scale = totalWork <= 0 ? 0 : (double) parentTicks / (double) totalWork;
         if ((style & PREPEND_MAIN_LABEL_TO_SUBTASK) != 0) {
             mainTaskLabel = name;
         }
     }

     /* (Intentionally not javadoc'd)
      * Implements the method <code>IProgressMonitor.done</code>.
      */
     public void done() {
         // Ignore if more done calls than beginTask calls or if we are still
 // in some nested beginTasks
 if (nestedBeginTasks == 0 || --nestedBeginTasks > 0)
             return;
         // Send any remaining ticks and clear out the subtask text
 double remaining = parentTicks - sentToParent;
         if (remaining > 0)
             super.internalWorked(remaining);
         //clear the sub task if there was one
 if (hasSubTask)
             subTask(""); //$NON-NLS-1$
 sentToParent = 0;
     }

     /* (Intentionally not javadoc'd)
      * Implements the internal method <code>IProgressMonitor.internalWorked</code>.
      */
     public void internalWorked(double work) {
         if (usedUp || nestedBeginTasks != 1) {
             return;
         }

         double realWork = (work > 0.0d) ? scale * work : 0.0d;
         super.internalWorked(realWork);
         sentToParent += realWork;
         if (sentToParent >= parentTicks) {
             usedUp = true;
         }
     }

     /* (Intentionally not javadoc'd)
      * Implements the method <code>IProgressMonitor.subTask</code>.
      */
     public void subTask(String name) {
         if ((style & SUPPRESS_SUBTASK_LABEL) != 0) {
             return;
         }
         hasSubTask = true;
         String label = name;
         if ((style & PREPEND_MAIN_LABEL_TO_SUBTASK) != 0 && mainTaskLabel != null && mainTaskLabel.length() > 0) {
             label = mainTaskLabel + ' ' + label;
         }
         super.subTask(label);
     }

     /* (Intentionally not javadoc'd)
      * Implements the method <code>IProgressMonitor.worked</code>.
      */
     public void worked(int work) {
         internalWorked(work);
     }
 }

